I was told to get a 556Nato cause they also shoots the 223. Also get the barrel that is 1:9 cause its in the middle and will should all gr ammo average. Now I'm wondering if anyone is selling a stripped lower and how much(please pm me). Also does anyone have a lower receiver parts kit? What should I go with? What are average prices. I want to upgrade most of the internal parts so then I am able to shoot it and not having to worry about taking it all apart. I was also told not to go cheap on the barrel. If anyone has anything to sell for a decent price that would be great. Please pm me guys. Thanks

No, a 1:9 twist rate is best suited for lighter grain ammo. 55gr max really.
The 1:7, like what I have, can shoot anything factory made that is 55+. Including 62, 75, etc. The 1:8 twist radius is supposed to be the middle man. However it probably shouldn't fire the two extremes 44 or 75.

The vast majority of stuff you find is 55. Frangible will be lighter, game hunting will be heavier.

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